


Just a Matter of Time

by rosegoldmarble



Category: Fullmetal Alchemist - All Media Types, Fullmetal Alchemist: Brotherhood & Manga
Genre: Gen, Other, Parental Roy, Parental Royed - Freeform, Parental!Royed, Time Travel
Language: English
Status: In-Progress
Published: 2017-08-23
Updated: 2018-03-25
Packaged: 2018-12-18 21:18:27
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 2,873
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11883015
Author URL: https://archiveofourown.org/users/rosegoldmarble/pseuds/rosegoldmarble
Summary: There was still an uneasiness in Fullmetal’s eyes, but he met the colonel’s gaze head on. “I didn’t lie. I’m biologically fifteen right now. I’m from about three years in the future.”---Fullmetal has been acting slightly off recently. Mustang isn't quite sure what to think of it. (This is, until the kid finally slips up.)--Chapter 2 is up!





	1. Chapter 1

Mustang’s slight suspicions amplified one afternoon when going over some reports with Fullmetal.

Fullmetal was sitting on his office’s couch, one arm hanging off the back of it, and one foot propped up on the coffee table. Mustang had given up on telling him not to months ago. 

“Colonel,” Fullmetal grumbled, “the coffee’s getting cold.” This was the third time Fullmetal had reminded him. Mustang frowned. Sure, he had left the pot on the table for about 20 minutes now, but that’s only because he was trying to decipher the kid’s handwriting - certainly not _his_ fault.

As Mustang squinted down at yet another scrawled out sentence - _did that say because or welcome?_ \- he registered the sound of Fullmetal sighing, muttering something along the lines of “ _Freaking lazy bastard_ ”, and the sound of coffee being poured into a mug. Then the sound of sugar cubes being plopped in.

When Mustang finally looked up, ready to ask the kid what he meant to say on the 4th paragraph of his report, he was surprised to see two coffee mugs filled, one pushed to the edge of the table nearest to him. Fullmetal fixed him with a defiant look, as if daring him to even mention the fact he had touched his coffee pot without permission.

Mustang sighed long-sufferingly, choosing to let this one go. He set the report down on the table in front of the other state alchemist in favor of his coffee. Fullmetal scowled, before relenting and picking it up. As Mustang reached for the sugar cubes, Fullmetal looked up from the report and said, “Oh, don’t worry, I got that already.”

Mustang froze. “What?” he asked, baffled.

Fullmetal waved a hand dismissively, glancing back down at the small stack of papers that he claimed passed as a proper report. “Already put in your sugar.”

“...What?”

“Already put in your sugar,” the kid repeated, distractedly. When Mustang didn’t respond after a few moments, he looked back up at his superior, irritation clear in his eyes. “What?”

The colonel took a sip of his coffee. It was _exactly_ how he liked it. He had never had coffee with Fullmetal before. And, Fullmetal had never seen him drink coffee, he was sure of it. He only ever drank tea in his office.

“How,” the colonel asked, becoming even more bewildered by the second, “did you know how I like my coffee?”

Fullmetal, who had been taking a long sip out of his own mug, suddenly stopped with a slight jerk. He cleared his throat, setting the cup down. “Uh, because you like an obscene amount of sugar in your coffee? I mean, five cubes? _Jeez_. A little hard to forget that.”

“You’ve never seen me drink coffee.”

“What? Of course I have.”

“We’ve never had coffee in my office.”

“Well, duh, I mean outside of your office, when you’re on break.”

Mustang narrowed his eyes. “I rarely ever do that.”

“Okay, rarely, sure, but you _have_. What the hell are you even on about?”

“And you counted how many sugar cubes I put into my coffee? _Five_?”

Fullmetal scoffed dismissively. “Look, I saw you dump a ton of sugar into your coffee a while ago, and it stuck with me because it was so goddamn ridiculous. You are a grown adult, and-”

“Five,” Mustang repeated slowly. “And you got the right amount of cream, too.”

“It was just a good guess! Jeez, why do you always have to pick apart _everything_ I do? Like this report,” Fullmetal snapped, waving the report once for emphasis.

Mustang had known the kid long enough to realize what he was doing. He was trying to divert the conversation, and get Mustang refocused on the report. The colonel sighed internally. He couldn’t win this battle, not this time. And there just wasn’t enough proof that something was amiss. Sure, it was strange, but…

“Fine, well, since you clearly have _such_ a good memory about mundane little things, I’m sure you will use your abilities to write a very detailed and _legible_ report tomorrow, to be put my desk no later than 5pm.” When Fullmetal didn’t respond at first, Mustang spoke up again. “Are we clear?”

The young state alchemist groaned boisterously, heaving himself to his feet. “Fine,” he said. “‘See you around, Colonel-bastard.”

Mustang would have called him a pipsqueak in return, if he wasn’t so wrapped up in his thoughts.

It had started a couple months ago. Every so often, Fullmetal would do or say something that seemed... off. But he had never confronted him about it, because the things were too small. (Much like a certain kid alchemist he knew.) The colonel had eventually decided he was just over-analyzing things. Teenagers’ moods and behavior changed all the time, after all.

But this was different. The way Fullmetal had reacted- choking on his coffee, trying to brush it off and redirect the conversation... definitely a little suspicious, to say the least.

How did he know how he liked his coffee?

\---

Mustang’s suspicions were validated a couple months later, before the ball the military held every spring.

Hawkeye was having trouble picking out a dress. Sheska had graciously offered to help her pick one out. Soon, everyone was in on it. Mustang was the person currently in possession of the dresses, having received them from Maes, the three of them hanging on his office door.

When Edward Elric slapped down his report on Mustang’s desk at 5:02pm sharp, he hadn’t expected a conversation. Usually the kid left without saying much at all. But instead, he glanced over at the dresses, brow furrowing. “Why do you have dresses hanging on your door?”

Mustang looked up from his book. “Oh, that,” he said. “Lt. Hawkeye still doesn’t have a dress for the ball the 22nd, and everyone wanted to pitch in and vote on which one she should wear. Don’t know why, but everyone, including the Lt., seems to find the whole thing amusing.”

Fullmetal made a sound of acknowledgement. Before he could turn to leave, Mustang asked, “So, which one do you vote for?”

“Hm.” Fullmetal walked over to the dresses, taking one off the door in order to inspect all three more carefully. “Well, she can’t wear this one,” the kid muttered, almost to himself, putting the backless dress behind the other two. “Maybe if I transmuted the fabric and stretched it-”

The colonel's heart nearly stopped.

“Fullmetal,” Mustang said, once he could find his voice. Fullmetal must have detected the strange emotion in his tone, because he quickly looked back at him.

“Yeah?”

“Why can’t Lt. Hawkeye wear a backless dress?”

Mustang had never seen the kid look so panicked. Which was saying a lot. He had seen him get in a fair share of dangerous situations. It scared the hell out of him, sometimes. Fullmetal was only fifteen. Impulsive, quick to fly off the handle. _"Don't die under my command, you're enough of a pain without the paperwork." Mustang once told Maes to tell Fullmetal. Maes had relayed back to him Fullmetal's response the next day._

_"He said," Maes was trying so hard to mask his grin, "And I quote: 'Tell him fine, there's no way I'm dying before you do, you morally bankrupt colonel with a god complex'."_

_Mustang had laughed._

“I, um, no, I didn’t say that?” Fullmetal flapped his hands in nervous dismissiveness. “I just meant the color doesn’t go with her eyes, and she doesn’t seem like a sequin kind of person-”

“Stop with the bullshit. I heard you talking about stretching the fabric so that it wasn’t backless. _What the hell is going on, Major Elric?_ ”

Fullmetal tensed at the use of his military title. “N-Nothing!” he insisted, voice raising an octave. “I don’t know what-”

“Why did you look so panicked when I asked why the Lt. can’t wear something backless? Answer me. _Now_ , damn it.”

Fullmetal’s anxious expression froze for a few moments before dissolving into pure frustration. “ _Shit_ ,” the state alchemist said emphatically, to no one in particular. “Fuck.”

“Any more expletives before you explain yourself?” Mustang asked, voice clipped and dangerous.

“ _Fuck_ \- okay,” Fullmetal said. “Okay, I’ll tell you.” His face became uncharacteristically solemn, and his fists clenched and unclenched. “But you have to promise to tell no one. And let me lock your door.”

Mustang took a deep breath.  “Fine. Then start talking. ”

Once he had locked the door, Fullmetal started to walk towards the desk, looking uncertain of himself.

“Sit,” Mustang bit out.

And he did, no arguments made. Fullmetal did not throw an arm back or a foot up, instead, he sat up straight, and hesitantly made eye contact with the colonel.

And said something impossible.

“I’m actually eighteen,” the kid said. “Well, almost nineteen now, I guess.”

“You- _what_?” Mustang was beyond flummoxed. “How- _how_ did you lie about your age? And why? And how does that explain how you know about Lt. Hawkeye?” Damn it, was the kid trying to divert his attention again with more lies?

There was still an uneasiness in Fullmetal’s eyes, but he met the colonel’s gaze head on. “I didn’t lie. I’m biologically fifteen right now. I’m from about three years in the future.”

 _Was there a proper response to such a statement?_ Mustang wondered faintly.

Fullmetal cautiously crossed his arms, waiting for a reply. When Mustang didn’t give him one, he ventured: “I- I know it’s hard to believe. But I can prove it to you.”

“Why can’t Hawkeye wear a backless dress?” Mustang asked again, voice barely above a whisper.

“Because of the burns. You burned the tattoos off her back. To erase her father’s research.”

“ _How_ ,” Mustang croaked. “ _How could you know_?” There was no way, no way in _hell._ No one else was ever told about the tattoos, he was sure of it. There were no records, _nothing_. 

“Because you and Hawkeye told me in the future. On my seventeenth birthday, actually.” His voice became almost wistful, reminiscent. Then he sighed, the moment passing. “Look,” he said, sounding even more on edge than before. "I hope I haven't just fucked everything up right now. I wasn't going to tell anyone. But I knew you weren't ever gonna let that one go. You never do." He rubbed his automail hand over his face. "God, I'm so stupid." 

They lapsed into silence. Mustang's mind was still reeling. Some things made sense now. How off Fullmetal had acted. The coffee.

"The coffee." Mustang said, not very eloquently.

"Oh. Yeah," he said, the corner of his mouth twitching up into a smile. "We've had coffee a few times in the future. Five cubes. I have one cube, like a normal person." 

"Well, that's just rude," Mustang scolded, almost automatically. Like his subordinate didn't just tell him he's from the future. Fullmetal didn't say anything, just stared at him. "...What is it?" the colonel asked tentatively.

"Nothing," Fullmetal replied, appearing to snap out of it. "It's just- that's what you said when I said that to you. I mean the first time. Or, the second time? Shit, I dunno." 

Mustang blinked, then rested his chin on his fist. "Tell me more. What else do you have that can prove it?"

"I..." Fullmetal paused for a moment, breaking eye contact again, then- "You told me about some days in...Ishval, once. One really boring story that I don't think you've told anyone else. You were alone for the day, scouting ahead or something, and you came across a snake," he huffs somewhat of a laugh, "and to distract yourself, you spent hours trying to think of a name for the snake."

Mustang feels something twist in his stomach.

"The worst ones I remember were Boots and Mr. Snake." The Fullmetal alchemist looks up at him, eyes searching. "I doubt you've told anyone that one, right? Too embarrassing."

"...You're right," Mustang says softly. "I haven't. But...why did I tell you?"

Suddenly, Fullmetal looks...sad, almost. "You were trying to distract me from something. Doesn't matter. What matters is I gotta stick to the plan, and you can't tell anyone."

"What plan? And why- _how_ are you here?"

The kid- or rather, technically an adult?- fixes him with a heavy stare. "I'm sorry, but I can't tell you any more. You're just gonna have to trust me."

Mustang was suddenly struck with the thought that Fullmetal was looking at him more like an equal than a miffed subordinate. His mind whirled with the implications, before settling on the fact that if Fullmetal came back on purpose- 

What was he trying to fix? 

 

 


	2. Chapter 2

**Notes for the Chapter:**

> Hey guys! I can’t believe it’s been about half a year since I’ve posted the first chapter. Thank you so much for all the support you’ve given! I never thought I’d get so many kudos and amazing comments!  
> Recently I’ve gotten my college workload much more under control (I posted the first chapter to this fic right before I started college), so I will definitely be updating this fic more often than every six months! I’m planning on updating it roughly once a month. And hopefully sometimes I’ll only have about a two week gap between chapters when I end up having more free time than usual. After mid-May, I’ll have a lot more free time. Anyways, thanks again for all your support!

The next day, Mustang prepared himself to stay late in the office, as he always did on days Fullmetal handed in reports. The kid would come in at least a couple minutes late, and then Mustang would have to sit him down in order decipher his ridiculously illegible handwriting. This, along with arguing about technicalities and the legality of certain actions (“alchemizing a park bench into a weapon in self-defense is _not_ legal, that’s public property, Fullmetal.”) usually resulted in Mustang leaving the office about twenty minutes late.

Just as Mustang sat down with his cup of tea and a book, the door opened. In walked Fullmetal, twenty minutes early.

“Hey,” Fullmetal said, closing the door behind him and walking briskly towards his desk. He barely made eye contact. “Here’s my report.” He tossed it on the desk, which landed dangerously near Mustang's cup of tea.

Mustang’s eyes narrowed in mild annoyance. “Thank you.” As he reached for it, Fullmetal turned on his heel and started to walk away. “Hey,” Mustang called, “we’re not done here.”

Fullmetal turned back around. “Is there a problem?” He asked.

The colonel quickly realized that there was not. Not only was the handwriting _legible,_ the report was absolutely normal, with nothing questionable or illegal on it. Mustang looked up.

“ _I can read this_ ,” Mustang said, his tone a mix of accusatory and awed.

Fullmetal blinked. “That’s good.”

“Care to explain why this is the _first_ time I can read your report?”

The teenaged alchemist shifted uncomfortably, before sighing and plopping himself down on the couch. Mustang watched as he didn't put his feet up on the coffee table. Instead, he looked behind him at the closed door. “I thought that would be obvious, considering what we talked about yesterday.” When Mustang didn't answer right away, he continued: “What, you thought my handwriting didn’t get any better in three years?”

“Ah.” Mustang looked down at the report again. “So. You faked your bad handwriting.”

“Yep. I was gonna gradually improve it, but since you know now…” Fullmetal trailed off, shrugging. “It’s more effort to fake bad handwriting.”

“So you wasted my time by coming late with illegible reports. For nothing.” He ran a hand over his face, feeling a headache coming on.

It looked like Fullmetal is trying to suppress a smirk. “Nothing personal, Colonel.”

“How did you get here?” Before Fullmetal could open his mouth, Mustang added sharply: “And _don’t_ say something like ‘by walking here’”.

Fullmetal’s eyebrows raised in apparent surprise. “Wow,” he said, leaning forward in his seat. “That _is_ what I was gonna say, Colonel. You sure you’re not from the future too?”

"Knock it off."

Fullmetal just rolled his eyes, and proceeded to ignore Mustang in favor of tightening the laces on his boot. 

Mustang considered the teenager in front of him, and the feelings he had been plagued with ever since yesterday rushed to the forefront of his mind. A part of him was happy to meet this eighteen-year-old Fullmetal, since it meant he lived that long. Considering all his past trauma and hardship, and the dangerous situations he had and surely will face as a state alchemist, it was a relief to know that Fullmetal reached adulthood. The other part of him is unsettled at just how different Fullmetal seems now. Sure, he was still the same kid with neatly braided hair and a terrible sense of fashion, but Mustang could tell by the way he held himself that there was something weighing him down. 

And he was terrified to find out what it was. 

"Can I go now?" Fullmetal asked, snapping him out of his thoughts. 

"Why are you here?"

"I _told_ you, I can't tell you that." 

"I know," Mustang said patiently. "I mean why are you _here?_ Instead of-"

"Instead of before I committed human transmutation, so I could stop myself?" Fullmetal interrupted. 

"Yes," Mustang said quietly. 

Fullmetal frowned deeply. "Because it's not possible." He suddenly lurched to his feet, and began to walk towards the door. "I gotta go - I promised Al I'd be back soon." 

 _Probably a lie_ , the colonel noted, but let it slide. "Does he know?"

" _No_ , so keep your mouth shut about it," he said, turning around to point a threatening gloved finger. 

Mustang opened his mouth to respond, but was stopped by his phone ringing. He brought it to his ear. "Hello? _Hughes_ , I don't really have time-"

"Say hi to him for me, Colonel-bastard," Fullmetal said offhandedly, and leaves. 

Mustang found himself staring after him long after he left, Hughes rambling about his family just background noise. 

**Notes for the Chapter:**

> This chapter is quite a bit shorter than normal, since I'm busy. Figured I'd post what I had, since it's been so long since I last posted. Hope you enjoyed anyways! Next chapter should be posted in April.


End file.
